This section describes approaches that could be employed, but are not necessarily approaches that have been previously conceived or employed. Hence, unless explicitly specified otherwise, any approaches described in this section are not prior art to the claims in this application, and any approaches described in this section are not admitted to be prior art by inclusion in this section.
A Low-power and Lossy Network (LLN) is a network that can include dozens or thousands of low-power router devices configured for routing data packets according to a routing protocol designed for such low power and lossy networks (RPL): such low-power router devices can be referred to as “RPL nodes”. Each RPL node in the LLN typically is constrained by processing power, memory, and energy (e.g., battery power); interconnecting links between the RPL nodes typically are constrained by high loss rates, low data rates, and instability with relatively low packet delivery rates. A network topology (a “RPL instance”) can be established based on creating routes in the form of a directed acyclic graph (DAG) toward a single “root” network device, also referred to as a “DAG root” or a “DAG destination”. Hence, the DAG also is referred to as a Destination Oriented DAG (DODAG). Network traffic moves either “up” towards the DODAG root or “down” towards the DODAG leaf nodes.
The DODAG can be formed based on a DODAG information object (DIO) advertised by the DAG root, where a “child” network device detecting the DIO can select the DAG root as a parent in the identified DODAG based on comparing metrics (advertised in the DIO) to a prescribed objective function of the RPL instance. The “child” network device, upon attaching to its parent, can output its own DIO with updated metrics that enable other network devices to discover the DODAG, learn the updated metrics, and select a DODAG parent.
Each child network device can unicast, up to the DODAG root, a destination advertisement object (DAO) message that identifies the child network device and its DODAG parent: if the DODAG is implemented in non-storing mode, the DODAG root creates a source-route path to a destination device based on recursively identifying the successive parents between the destination and DODAG root, as identified in the received DAO messages.